Improvement in cut-offs foe steam-engines



GEORGE J.LRO?BERTS, OF DAYTON1 OHIO.

Letters .Patent N0. 82,556, dated September 29, 1868.r

IMPROVEMENT IN GUT-OFFS FOR STEAM-ENGINES.

i @te .tlgehnle referat tu iu these lettsts rteut mit making :,mrt nf tlg same.

TO ALL WHOM IT MAY CONCERN:

Be it known that I, GEORGE J. ROBERTS, of Dayton, in the county of Montgomery, and State of Ohio, have invented a new and useful Improvement in Variable Cut-Oli` Steam-Valve Gear; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable those skilled in the art to make and use the same, reference being had to the accompanying drawings, formingipart of this specification.

This invention consists in the devices for operating the induction-valves'of a steamlengne, that the quantityof steam admitted into the cylinder shall depend upon the speed and be made variable, according to the' power required.

Figure 1 is a sectional elevation of the valve-gear and valves, showing the general arrangement and method of operation.

Figure 2 isa vertical cross-section of tig. 1,7through the line x x, showing-the variable slide, and the arm by which it is moved, and the cam by which the valve is lifted.

Figure 3 is va horizontal section of iig. 2, through the line yy, showing the position of the valves and the induction and eduction-ports of the engine. l i

Similar letters 'of reference indicate corresponding parts.

A represents thecylinder of the engine. i

B is the-steam-chest.

C represents the valve-seats, which are cast with the chest.

D is the steam or induction-valve, and

E is the exhaust or' eduction-valve.

r F is the valve-chest cover.

gg are passages from the induction-chamber L to the cut-ofi valves I).

g indicates the passage from the cut-cti` valve to the cylinder.l y

J represents the passage for the exhaust steam, which communicates with the exhaust-valves E.

The valves are lifted or opened by cams on the revolving shaft L.

Ml is the cam by which the cut-off valve is opened.

N is a slide or lifter, on which thc cam M operates to lift the valve. The position of this slide N is varied by the speed of the engine. The amount of steam admitted to the cylinder is controlled by the hold which the cam in its revolution takes upon the slide This slide is attached to the arm o on the shaft P, and the shaft P is connected with the governor of the engine by the arm g and connecting-rod R.

When the engine is running at a given or the required speed, the arm o-will stand stationary, but if, from the throwing o` orV on of machinery, or from any other cause; the speed is either checked or accelerated, the arm o and slide N will be moved either toward or from the cam, thus giving the cam more or less hold of the slide, and consequently raising the valve moreor less for. the passage of steam to the cylinder.

For the purpose of insuring the closing of the valves, I apply spiral or other springs to the upper stems,

as seen in the drawing at S.

The lower stems-of the valves are marked t.

The exhaust-valves are raised by a cam on the revolving shaft L, and are held open during the whole length4 of the return-stroke, thus giving time for all the steam to escape from the cylinder before the piston arrives at the end.

Springs or rubber cushions may be placed so as to receive the drop" 'of the valves and prevent injurious concussion. `l

A cut-oft" and an exhaust-valve are employed for each end of the cylinder, as seen in the drawing.

I claim as new, and desire to secure by Letters Patent- 1. The valves D E and the seats C C, constructed as herein set forth.

2. The arrangement ofthe slide N, cam on, arm o, shaft Rarm g, and connectingrod R, as herein set forth.

GEO. J. ROBERTS.

Witnesses:

JAS. H. BROWNELL, Trios. D MrrcnnLL. 

